Underwater photography is a specialized undertaking that requires specialized equipment. One challenge is the loss of color and contrast when relying upon natural sunlight. The longer wavelengths of sunlight are absorbed quickly by the surrounding water, so objects appear blue-green in color to the human eye and cameras. This loss and shift of color occurs both with increasing water depth as well as horizontal distance between the camera and subject. Thus subjects that are further away from the camera can appear generally colorless but with a blue tint. This effect is true even in apparently clear ocean water.
One method of addressing this problem is to place the camera as close as possible to the subject and the water's surface thus minimizing the loss of color. Another method, which can provide a greater opportunity for improved image color and quality, involves the use of flash or strobe lighting to restore color that otherwise would be lost. The use of a flash or strobe light is often viewed as a difficult aspect of underwater photography. As mentioned color is absorbed as light travels through water. The deeper one dives, the less reds, oranges and yellow colors from the natural light remain visible. A strobe light replaces that color, as well as helps to provide shadow and texture.
Another complication is what is known as “backscatter” which occurs when the light from an artificial light source reflects particles in the water. Even seemingly clear ocean water often contains large quantities of this particulate which usually is not readily seen by the human eye. One method of addressing this problem is to locate the light source away from the axis of the camera lens. Thus oriented the light normally will not reflect the water particles located in front of the lens in a direction toward the lens, but the light will still illuminate the subject. Various types of attachments are used to make off-camera strobes easier to use.
Thus while strobe lights provide a valuable source of light when underwater, many conventional lights have limitations. Because of the rapid loss of light as a function of distance underwater, strobes have a limited range. Moreover, maintaining a relatively small physical size of strobe light units is important, since underwater portability is often a requirement in this environment. Given the above-described challenges and limitations, there remains a need for improved equipment for underwater lighting.